Surgical devices are used in various open, endoscopic, and laparoscopic surgeries to seal and transect tissue volumes and blood vessels. The devices generally include jaws for grasping tissue therebetween and a cutting mechanism that is advanced through the grasped tissue to transect it. In some instances the devices are configured to apply electrical energy to the grasped tissue to seal it before tissue transection is completed. For example, various mono-polar and bi-polar radio frequency (RF) surgical instruments and surgical techniques have been developed for sealing tissue volumes and blood vessels. Electrodes can be disposed on a face of one or both of the jaws and can apply energy to the grasped tissue to promote hemostasis.
One issue that can plague electrosurgical devices of the nature described above is the amount of compression supplied to tissue volumes or blood vessels by the jaws prior to transection. While RF energy is being delivered to tissue grasped by the jaws, the amount of compression supplied by the jaws to the grasped tissue can actually decrease. This can occur because the grasped tissue can become thinner as the energy is applied to it. Generally, the thicker the tissue or vessel, the more pronounced the decrease in compression can be. An insufficient amount of compression supplied by the jaws to the tissue can cause the tissue to undesirably slip. In an effort to counteract this tendency, devices may be designed with very tight tolerances to try and reduce the likelihood of slippage. Such efforts are not always successful, however, and furthermore reliance on tight tolerances can negatively impact the manufacturing process. Additionally, some efforts to maintain or supply additional compressive force to the jaws of some electrosurgical devices can result in undesirable initial loads being applied to the cutting mechanism. High levels of load placed on the cutting mechanism prior to transection can negatively impact the performance of the cutting mechanism.
Accordingly, there remains a need for improved surgical devices that maintain and/or increase the amount of compressive force supplied by its jaws to tissue grabbed therebetween without applying unnecessary loads to the cutting mechanism of such devices.